Not that these are the most amazing images ever (they weren't meant to be artistic, just routine work), but I enjoyed them. They're from a project on rotifers by one of my undergraduate thesis students. They're both of Adineta vaga: the first is of the whole animal (the pink spots are the DNA), the second is the musculature on a confocal laser microscope. (Photos by K. Ashforth).
Here are some pictures I took several years ago. A is an ovariole from the ovary of a vinegar fly (Drosophila melanogaster) and B is the same from a flea (Ctenocephalides felis). The huge circles are nurse cells, which are very highly endopolyploid.